Stable dental analog

ABSTRACT

An implant analog includes an abutment that can be mounted in the dental lab replica of the relevant section of a patient&#39;s mouth more securely than heretofore possible. Because of the implant analog, a crown will attach more accurately to the implant in the patient&#39;s mouth. The analogs have a pin or other protrusion that projects from the base of the analog. The analog has substantially the same height and dimensions as a conventional implant and abutment.

FIELD OF THE INVENTION

[0001] This invention relates generally to the construction of a dentalprosthesis that is attached to an implant in the bone of a person's jaw.

BACKGROUND OF THE INVENTION

[0002] Dental implants are a common treatment for the replacement of amissing tooth or missing teeth. An implant is placed into the bone in aperson's jaw in a variety of fashions and using a variety of systems.The bone and the implant adhere together in a process known asosseointegration, thus enabling a person to have a new tooth or set ofteeth held into position in the jaw utilizing screws to hold them down.

[0003] Many firms manufacture complete systems of dental implants andprosthetic components for subsequent attachment to the implant. In atypical construction, the implant has an axially threaded hole at itstop, that is, the proximal end, near the gum surface. After the implanthas integrated with the bone, the gum of the implant is opened to exposethe tapped hole. Then a transmucosal abutment is attached to the tappedhole of the implant and extends to a level above the gum orsubstantially to the gum surface. The protruding free end of theabutment is constructed for attachment of a prosthesis. For preventingrotation of the prosthesis, the protruding end of the abutment requiresa non-round shape and a hexagon protrusion has been widely used. Arecessed hexagon is also popular with some systems. The abutment alsoincludes a central threaded hole concentric with the threaded hole ofthe implant and extending inward toward the jaw bone.

[0004] A false tooth or frame is provided with a hole therethrough,known in the industry as a chimney, and a non-round recess in its basecorresponds in shape to the protruding non-round cross section for theabutment. Thereby, the crown can be connected to the abutment andrelative rotation between them is prevented so long as critical contoursof the abutment and the recess in the crown are maintained.

[0005] To prevent the crown or bridge from lifting axially from theabutment, a final screw is passed into the chimney opening and engagesthe tapped hole in the implant by way of the abutment so as to hold thecrown axially to the abutment and to the implant. Thus, the crown cannotrotate about the abutment or implant because it is mated with thespecial contours on the exposed end of the abutment. The abutment issimilarly mated to the proximal or outer end of the implant. The crowncannot pull away from the abutment when the screw has been tightenedinto place.

[0006] Finally, the chimney above the screw is filled with a compositematerial that hardens and is shaped as part of the crown to look lie anatural tooth.

[0007] There are many variations in construction.

[0008] In an alternative method, the crown is attached directly to anon-round protrusion of the implant and is held directly to the implantby a gold screw without use of an intermediate abutment.

[0009] The implant is intended to be a permanent fixture in the jawbone. The abutment and crown may be replaced if necessary due to damageor poor fit by gaining access to the screw head by way of the chimney,and backing off the screw so that the crown and abutment or crown to theimplant can be separated from the implant. Thus repairs may be made ofan abutment and crown with no or little inconvenience.

[0010] Therefore, the fit of an implant with the crown or frame must beperfect. If a prosthesis is placed into the mouth and does not seatcorrectly, the implant or abutment can be damaged. If an implant isdamaged there are not many options for its repair. In cases where therehave been a poor fit, the screws have broken inside the abutmentrequiring the replacement of the abutment. There have been cases wherethe screw broke inside the implant. The implants cannot be replacedwithout surgically removing them. Placing a new implant in the same spotis not an advised option.

[0011] Among related patents disclosing dental analogs include U.S. Pat.No. 6,142,782 of Lazarof, which shows a dental analog with annularwings. However, the annular wings do not hinder rotating and thereforemisplacement of the analog within the replica cast stone. The annularwings of Lazarof do not intersect with the cast stone material enough toprevent rotation.

OBJECTS OF THE INVENTION

[0012] Accordingly, it is the object of the invention to provide amethod for insuring the most accurate seating possible of a prosthesisto an abutment or implant.

SUMMARY OF THE INVENTIONS

[0013] The present invention comprises an implant analog that mayinclude a standard abutment that can be mounted in the dental labreplica of the relevant section of a patient's mouth more securely thanheretofore possible. Because of the inventive implant analog, dentallabs can now create a crown that will attach more accurately to theimplant in the patient's mouth. The analogs of the present invention aredesirably longer than the analogs used heretofore and have a pin thatprojects from the base of the analog. Desirably, the inventive analogshave a side ridge. Moreover, the analog has substantially the sameheight and dimensions as a conventional implant and abutment. In apreferred embodiment, the analog of the present invention is formed fromstainless steel.

[0014] A careful confidential experiment was conducted at New YorkUniversity of School of Dental Medicine by Dr. C. Jager, Dr. G. R.Goldstein, Dr. E. Hittelman and the Applicant herein. The experiment wasdesigned to compare the performance of a prior art analog of NOBELBIOCARE®, as shown in FIG. 9, to that of one embodiment of the presentinvention, as shown in FIG. 4. A statistically significant improvementfor the present invention was found in terms of framework fit. Also,resistance to applied torque was found to be significantly improved forthe analog of this invention.

[0015] The experiment evaluated torque prostheses to laboratory dentalimplant analogs. The study evaluated the movement of the prior artanalog of NOBEL BIOCARE®, as shown in FIG. 9, and the embodiment shownin FIG. 4 of the present invention. Both were torqued to 20 Ncm in areinforced type IV die stone. 80 analogs were divided into groups of 4analogs, including three of the prior art analog shown in FIG. 9 withone of the present invention shown in FIG. 4. These analogs wereembedded in thirty equal blocks of Type IV plaster stone using aprefabricated four unit implant framework. Of the twenty analogs, tenwere imbedded in the stone at a depth of four cm and ten were imbeddedat a depth of six cm from the implant platform. These groups of ten werethen divided into groups of five each, where five of the prior artanalogs shown of the present invention in FIG. 9 were torqued to 20 Ncmin each group and five analogs shown in FIG. 4 were torqued to 20 Ncm.The initial framework was used to evaluate the fit of each analogtherein. In the 4 mm depth group of the prior art shown in FIG. 9, twoof the five samples (40%) did not allow the framework to fit the analog.In the 6 mm depth of the prior art analogs shown in FIG. 9, three of thefive samples (60%) did not allow the framework to fit. However, all ofthe dental analogs shown in FIG. 4 of the present invention fit back tothe cast.

[0016] As a result, the analogs of the present invention, as shown inFIG. 4, were able to resist movement within a stone cast when torqued,unlike a significant portion of the prior art dental analogs shown inFIG. 9.

[0017] Therefore, the dental analogs of the present invention haveunexpected, beneficial results not achievable with the dental analogs ofthe prior art shown in FIG. 9.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1 is a view of a dental lab replica showing the position ofan analog and an abutment;

[0019]FIG. 2 is a view of a lower jaw about to receive a prosthesis andhaving two implants;

[0020]FIG. 3 is a view of an embodiment of the present inventionincorporating a conical abutment;

[0021]FIG. 3A is a partial view taken within the phantom circle of FIG.3A, shown rotated ninety degrees for clarity;

[0022]FIG. 4 is a view of an embodiment of the present inventionincorporating a standard abutment;

[0023]FIG. 5 is a view of an embodiment of the present inventioncorresponding to an implant with a hexagonal protrusion;

[0024]FIG. 6 is a view of an embodiment of the present inventioncorresponding to a large diameter implant with a hexagonal recess;

[0025]FIG. 7 is a side elevation view in partial cross section of anembodiment of the present invention corresponding to an implant with ahexagonal recess;

[0026]FIG. 7A is a top plan view thereof;

[0027]FIG. 8 shows a conventional impression coping with depthindications from 2-5 mm;

[0028]FIG. 9 shows a conventional prior art fixture replica, or analog,which is replaced by analog according to the present invention;

[0029]FIG. 10 shows the placement of a fixture replica, either aconventional or according to the present invention, in the lab replicathat is to be secured to an abutment and a crown via a guide pin;

[0030]FIG. 11 shows the attachment of a fixture replica, either aconventional or according to the present invention, to an impressioncoping that is fixed in an impression of the relevant section of apatient's mouth prior to the casting of the lab replica;

[0031]FIG. 12 shows a dental impression tray modified to provide accessto the impression coping that is secured to the implant in a patient'smouth by a guide pin;

[0032]FIG. 13 shows the excess material around the impression coping ina tray containing impression material, the impression coping beingsecured to the implant in the patient's mouth by a guide pin;

[0033]FIG. 14 shows a means of securing the impression coping to thetray containing the impression material with an acrylic resin;

[0034]FIG. 15 shows the impression containing the impression coping;

[0035]FIG. 16 is a top view of an engagement plate of this inventionwhich is used to provide improved anchorage for a conventional analog;

[0036]FIG. 17 is an exploded side view of the engagement plate of FIG.16 attached to a conventional analog;

[0037]FIG. 18 is a perspective view of an analog body with a transversetube configured to screw into a variety of abutments;

[0038]FIG. 19 is a perspective view of an analog body with transversewings;

[0039]FIG. 20 is a bottom view of an analog body with transverse wings;

[0040]FIG. 21 is a perspective view of an analog body with coplanartransverse tubes at right angles;

[0041]FIG. 22 is a perspective view of an analog body with non-coplanaroblique tubes;

[0042]FIG. 23 is a bottom view of an analog body with eight co-planartransverse tube segments;

[0043]FIG. 24 is a perspective view of an analog body with angledspikes;

[0044]FIG. 25 is a side elevation of an analog body with serrated sideextensions;

[0045]FIG. 26 is a side elevation of an analog body with four serratedand perforated side extensions; and,

[0046]FIG. 27 is a perspective view of an analog body with looped sideextensions.

DETAILED DESCRIPTION OF THE INVENTION

[0047] Simplified, the construction of the prosthesis begins after theosseointegration of the implant with the dentist making an impression ofthe relevant section of the patient's mouth. When constructing theprosthesis, the dentist makes an impression including an impressioncoping. Desirably, the impression material employed is hard and elasticwhen set, such as the materials sold under the trade names Impragum,Express and President.

[0048] Once the impression material hardens, the tray containing theimpression is sent to a dental lab where the prosthesis is made. Thedental lab uses this impression to make a replica of the relevantsection of the patient's mouth. Typically, the replica is made ofgypsum, and is made to reproduce the milieu into which the prosthesis isto fit, including, for example, any hexagonal protrusion or recession inthe abutment the dentist is using.

[0049] For example, FIG. 1 shows a view of dental lab replica 130 withanalog 120 and abutment 110.

[0050] Moreover, FIG. 2 shows an actual patient lower jaw with twoimplants 220, a three tooth prosthesis 210 and screws 230 to retainprosthesis 210 in implants 220.

[0051] In making the impression, the impression coping is attached tothe implant in the same way the final prosthesis will attach. Theimpression coping rests flush on top of the implant, or implant andabutment, with a guide screw passing through and into the implant. Theimpression coping remains in the impression in the same position thatwas in the mouth and the guide screw must be removed before theimpression can be removed from the patient's mouth.

[0052] In making the dental lab jaw model, or replica, the analog isattached to the impression coping with a guide screw going through theimpression coping and into the analog. All of the teeth in the relevantportion of the mouth are replicated in the model, which desirably ismade of gypsum. The goal is to have the analog in the replica in theposition that corresponds to the position of the implant in thepatient's mouth, including the orientation of any protrusion or recess.

[0053] The present day tools offered by the implant manufacturersutilize brass or stainless steel analog.

[0054] The configuration of the prior art analogs replicates theinternal thread dimension of the implant or abutment and copies theshape of the external or internal hexagon. However, the outside diameterof a prior art analog maintains a shape that is not consistent with theneeds of the dentist or technician in constructing the prosthesis.Conventional analogs are too small and are removed from the gypsum modeltoo easily. Moreover, the exterior surface of conventional analogs aretoo smooth which permits the analog, and thus the prosthesis, to rotatein the model during construction of the prosthesis. Such rotation movesthe hexagonal position of the prosthesis into a position that does notmatch the corresponding position of the implant in the patient's mouth.

[0055] In contrast to the prior art conventional, easily rotatable anddislodgable dental analogs, the present invention is a new analog thatwill not allow any rotation in the gypsum model. In a preferredembodiment, as shown in FIGS. 3 and 3A, the analog 320 of the presentinvention is substantially longer and has a unique feature of atransverse pin 312 or other protruding geometric shaped member extendingthrough hole 314 in its side.

[0056]FIG. 4 shows analog 420 with abutment 22 and hole 414 forinsertion of a pin therein, similar to pin 312 of FIG. 3A.

[0057] As shown in FIGS. 5, 6, and 7, these dental analogs 520, 620 and720 of the present invention are preferably ridged with annularrecesses, these dental analogs 520, 620 and 720 on their respectivesides to gain better retention inside the gypsum model.

[0058] Analogs 420, 520, 620 and 720 have respective pins (not shown)similar to transverse pin 312 of analog 320 of FIG. 3A. These pins 312are located at the base of the respective analogs 320, 420, 520, 620 and720 to lock the position. These transverse pins 312 prevent horizontal,vertical or cylindrical movement of the analogs 320, 420, 520, 620, and720 within the model.

[0059] Conventional implants have a standardized system of heights,measurements and dimension for implants and abutments. The respectiveinventive analogs 320, 420, 520, 620, 720 of the present invention canhave a shape which incorporates a conical abutment 322 (FIGS. 3 and 3A),a standard abutment 422 (FIG. 4), a hexagonal protrusion 522 (FIG. 5), alarge hexagonal recess 622 (FIG. 6) or a hexagonal recess 722 (FIG. 7),as these terms are used in the dental industry.

[0060] Analogs 520, 620 and 720 also bear annular grooves 516, 616 and716.

[0061] The analogs 320, 420, 520, 620 and 720 of the present inventionare machined to specified mechanical tolerances. In particular, theinternal thread of the inventive analogs are closer to the threads ofactual implants and abutment. This closer approximation to the actualimplants insures that the guide screw goes into the implant the samenumber of turns the guide screw goes into the analog, and maintains theprosthesis in the same position relative to the patient's mouth as theprosthesis had with respect to the replica. The internal or externalhexagon is also closer in dimensions to the actual implant. As a result,the prosthesis will fit on the analog and on the actual implant orabutment in the manner intended.

[0062] Another complication in the construction of dental analogs isthat it is often necessary to construct a large frame using solderedconnections. The present methods of soldering require a duplicate modelof high heat tolerance gypsum investment be made with the present dayanalogs. The frame is soldered on that model. The success rate of thesesolder connections is far lower than expected in the industry. Thepresent invention allows a more accurate solder connection. The presentinvention also holds better in the invested model and keeps the analogsfrom moving in the model.

EXAMPLE

[0063] In the single tooth prosthetic work, the impression is taken fromthe fixture level. As shown in FIG. 8, one type of conventionalimpression coping 800 has an internal hexagon at the base, whichcorresponds to the hexagon of the abutment. The coping has depthindications for assessment of proper abutment size, 2 mm, 3 mm, 4 mm,and 5 mm. The upper margin of the abutment-like part indicates 6 mm. Theimpression coping is typically made of titanium.

[0064] The impression coping is used together with a special guide pin(e.g., a DCA 098), 850, for a single tooth (the guide pin used to securethe prosthesis to the implant typically has a different thread).

[0065] Typically, in the laboratory, any undercuts of the impressioncoping are blocked out before pouring the impression (including thedepth indications). This blocking is especially important when thelongest abutment is used. This precaution prevents fracturing the castwhen separating the model and the impression coping.

[0066] During the Laboratory procedure, an analog, for example aconventional prior art analog 900 shown in FIG. 9, or an analog of thepresent invention such as the analogs of FIGS. 3-7, is used in thelaboratory jaw model, or replica, to represent the implant in theworking cast. This is illustrated in FIG. 10 where analog 1000 is set inthe laboratory jaw model, or replica, 1010, and the abutment 1020 andcrown 1030 are secured to the jaw model by guide pin 1040. The analoghas the same top hexagon and internal thread as the implant. In contrastto the stainless steel analogs of the present invention, conventionally,analogs were typically made of nickel-plated brass.

[0067]FIG. 11 shows an impression 1100 containing an impression coping800 being attached to an analog 1000 via guide pin 1040. Once the analog1000 is secured to the impression coping 800 by the guide pin 1040, theimpression 1100 is used to cast he laboratory jaw model, or replica,from stone, such as gypsum.

[0068] The impression 1100 containing the impression coping 800 can beprepared in any conventional manner. For example, as shown in FIG. 12,one can make a hole 1200 in an acrylic-resin stock tray 1210 for accessto the impression coping 800 which is secured to the implant by theguide screw.

[0069]FIG. 13 shows tray 1210 loaded with an impression material ofchoice 1300 in the mouth with impression coping 800 secured to implant120 within the patient's jaw 1310.

[0070]FIG. 13 also shows the removal of any excess material aroundimpression coping 800 once impression material 1300 has set.

[0071] Impression coping 800 is then secured to tray 1210 withauto-polymerizing acrylic resin 1400. The orientation of the hexagonalhead of the implant 120 should be maintained when the impression 1100 isremoved. Next, guide pin 850 is unscrewed and impression 1100 iscarefully removed form the patient's mouth.

[0072] As noted before, FIGS. 3-7 show different embodiments of thedental analogs 320, 420, 520, 620 and 720 of the present invention eachusing a transverse rod pin 312 or tube within hole 314, 414, 514, 614,or 714, in the base section of each analog 320, 420, 520, 620, or 720 toenhance the anchoring of the analog in the plaster of the replica. Eachof the different embodiments uses a different style of abutment 322,422, 522, 622, or 722 to match that which the dentist had used in thepatient's actual implant.

[0073] For example, FIG. 3 shows a conical abutment 322 for analog rod320 and FIG. 4 shows a standard recessed abutment 422 for analog rod420. FIG. 5 shows an abutment 522 with a hexagonal protrusion for analogrod 520, FIG. 6 shows a large diameter abutment 622 with a hexagonalrecess, for analog rod 620, and FIG. 7 shows an abutment 722 with ahexagonal recess for analog rod 720.

[0074]FIG. 16 shows another embodiment of this invention in the form ofa flat engagement plate 2000 which is used to provide enhanced anchoringof a standard prior art analog 900 (see FIG. 9) in the replica plaster.

[0075] As shown in FIG. 17, the conventional analog 2003 is insertedthrough central hole 2001 and adhesively bonded 2004 at an obliqueangle. Perforations 2002 enhance adhesion to immobilize plate 2000 inreplica plaster. An optional hollow sleeve 2005 can be used to extendthe vertical height of analog 2003, to further promote its anchoringwithin the replica plaster.

[0076] It is further noted that optional removable hollow sleeve 2005can also have any of the protrusions shown in the other drawing figures,such as protrusion rods 2012 of FIG. 18 or FIG. 21, protrusion 2022 ofFIG. 19, protrusion wings 2030 of FIG. 23, protrusion barbs 2032,protrusion wings 2035 of FIG. 25, protrusion wings 2040 of FIG. 26 orprotruding loops 2051 of FIG. 27.

[0077]FIG. 18 shows the concept for a series of additional embodimentsof analogs of this invention which use a tubular body 2010 with externalthreads 2011 at the top end. These threads screw into mating femalethreads on a series of abutments 2013 (here illustrated as a conicalabutment) which are supplied to match the style and size actuallyimplanted in the patient's jaw.

[0078] Therefore, analogs of this general category of embodiments can bematched with a variety of abutments 322, 422, 522, 622, or 722(asdescribed in FIGS. 3-7). The analog 2010 with conical abutment 2013 ofFIG. 18, similar to analog 320 with a conical abutment 322, uses atransverse tube or rod 2012 to aid in anchoring body 2010 in plaster.Slotted body 2020 as shown in FIG. 19 accepts two rectangular wings 2021(as shown in bottom view of FIG. 20) with perforations 2022 as yetanother embodiment to resist rotation within, and extraction from, thereplica plaster.

[0079] The embodiment shown in FIG. 21 uses coplanar radial transversetubes 2012 at right angles to each other to provide anchorage.

[0080] The embodiment shown in FIG. 22 uses two oblique tubes 2012 whichpenetrate body 2010 as anchorage.

[0081] The bottom view of the embodiment of FIG. 23 shows eight equallyspaced tubular segments 2030 attached to body 2010 to provide anchoragein replica plaster.

[0082]FIG. 24 shows an embodiment of an analog using tubular body 2031with upward angled spikes 2032 in two rows to provide anchorage.

[0083] The embodiment of FIG. 25 shows slotted body 2020 with a pair ofserrated triangular wings 2035 to provide anchorage in the replicaplaster.

[0084]FIG. 26 shows an embodiment of an analog with body 2039 with fourslots accommodating four perforated and serrated triangular wings 2040to rigidly anchor it to the plaster of a replica.

[0085] Furthermore, FIG. 27 shows an embodiment of an analog usingtubular body 2050 with one or more outwardly extending looped extensions2051 to promote anchorage.

[0086] It is further know that other modifications may be made to thepresent invention without departing from the scope of the invention, asnoted in the appended claims.

I claim:
 1. An anchored anti-rotation analog post for preparing dentalcrown for insertion into the mouth of patient, said analog postcomprising: an elongated pin having opposite top and bottom ends; saidpin having at least one anti-rotation anchoring projection extendingdiscretely and radially from said pin near said bottom end thereof. 2.The device of claim 1 wherein said pin has a circular cross-section. 3.The device of claim 1 wherein said pin has an elliptical cross-section.4. The device of claim 1 wherein said pin has a polygonal cross-section.5. The device of claim 4 wherein said pin has a triangularcross-section.
 6. The device of claim 4 wherein said pin has a squarecross-section.
 7. The device of claim 4 wherein said pin has arectangular cross-section.
 8. The device of claim 4 wherein said pin hasa hexagonal cross-section.
 9. The device of claim 1 wherein said atleast one anchoring projection comprises a pair of opposing radiallyextending projections.
 10. The device of claim 1 wherein said at leastone anchoring projection comprises at least two pairs of opposingradially extending projections.
 11. The device of claim 9 wherein saidat least two pairs of said opposing radially extending projections arespaced apart longitudinally on said pin near said bottom end thereof.12. The device of claim 9 wherein said at least one pair of opposingradially extending anchoring projections comprises rigid loops.
 13. Thedevice of claim 9 wherein said at least one pair of opposing radiallyextending anchoring projections comprises rigid rods.
 14. The device ofclaim 9 wherein said at least one pair of opposing radially extendinganchoring projections comprises rigid plates having a center slot, saidcenter slot disposed in a matching slot disposed in the lower end ofsaid pin, said lower-end pin slots for receiving and securing said rigidplates.
 15. The device of claim 9 wherein said at least one pair ofopposing radially extending anchoring projections comprises rigidserrated barbs.
 16. The device of claim 15 wherein said barbs aretapered to have a smaller radial extension toward the lower end of saidpin.
 17. The device of claim 15 wherein said barbs are tapered to have asmaller radial extension toward the upper end of said pin.
 18. Thedevice of claim 10 wherein said at least two pairs of said opposingradially extending projections are spaced apart longitudinally on saidpin near said bottom end thereof.
 19. The device of claim 10 whereinsaid at least one pair of opposing radially extending anchoringprojections comprises rigid loops.
 20. The device of claim 10 whereinsaid at least one pair of opposing radially extending anchoringprojections comprises rigid rods.
 21. The device of claim 10 whereinsaid at least one pair of opposing radially extending anchoringprojections comprises rigid plates having a center slot, said centerslot disposed in a matching slot disposed in the lower end of said pin,said lower-end pin slots for receiving and securing said rigid plates.22. The device of claim 10 wherein said at least one pair of opposingradially extending anchoring projections comprises rigid serrated barbs.23. The device of claim 22 wherein said barbs are tapered to have asmaller radial extension toward the lower end of said pin.
 24. Thedevice of claim 22 wherein said barbs are tapered to have a smallerradial extension toward the upper end of said pin.
 25. The device ofclaim 9 wherein said pin comprises a receptacle sleeve for securelyreceiving a conventional dental crown analog post.
 26. The device ofclaim 10 wherein said pin comprises a receptacle sleeve for securelyreceiving a conventional dental crown analog post.
 27. A method ofpreparing dental crowns efficiently and accurately, comprising the stepsof a. preparing an analog dental crown mounting pin having at least onepair of radially extending anchoring extensions disposed near a bottomend of said pin; b. inserting bottom-end-down said prepared mounting pininto a dental crown casting mold; c. securing said prepared mounting pintemporarily in place within said casting mold; d. adding settableplastic molding material to said casting mold so as to embed said bottomend of said pin by surrounding said bottom end of said pin with saidplastic molding material; e. allowing said plastic molding material toset and harden with said prepared pin embedded within said moldingmaterial; f. proceeding with conventional steps in dental crown-makingbased upon utilization of said firmly anchored and secured analog pin.28. The method of claim 27 wherein said pin comprises at least one pairof anchoring projections oppositely and radially extending from a bottomend of said pin.
 29. The method of claim 27 wherein said pin comprisesat least two pairs of anchoring projections oppositely and radiallyextending from a bottom end of said pin and wherein said at least twopairs of said projections are spaced apart longitudinally on said pinnear said bottom end thereof.
 30. The method of claim 28 wherein said atleast one pair of opposing radially extending anchoring projectionscomprises rigid loops.
 31. The method of claim 28 wherein said at leastone pair of opposing radially extending anchoring projections comprisesrigid rods.
 32. The method of claim 28 wherein said at least one pair ofopposing radially extending anchoring projections comprises rigid plateshaving a center slot, said center slot disposed in a matching slotdisposed in the lower end of said pin, said lower-end pin slots forreceiving and securing said rigid plates.
 33. The method of claim 28wherein said at least one pair of opposing radially extending anchoringprojections comprises rigid serrated barbs.
 34. The method of claim 33wherein said barbs are tapered to have a smaller radial extension towardthe lower end of said pin.
 35. The method of claim 33 wherein said barbsare tapered to have a smaller radial extension toward the upper end ofsaid pin.
 36. The method of claim 29 wherein said at least one pair ofopposing radially extending anchoring projections comprises rigid loops.37. The method of claim 29 wherein said at least one pair of opposingradially extending anchoring projections comprises rigid rods.
 38. Themethod of claim 29 wherein said at least one pair of opposing radiallyextending anchoring projections comprises rigid plates having a centerslot, said center slot disposed in a matching slot disposed in the lowerend of said pin, said lower-end pin slots for receiving and securingsaid rigid plates.
 39. The method of claim 29 wherein said at least onepair of opposing radially extending anchoring projections comprisesrigid serrated barbs.
 40. The method of claim 39 wherein said barbs aretapered to have a smaller radial extension toward the lower end of saidpin.
 41. The method of claim 39 wherein said barbs are tapered to have asmaller radial extension toward the upper end of said pin.